Filter device for fluids

ABSTRACT

The invention relates to a filter device for fluids, comprising a housing ( 1 ) accommodating at least one filter element ( 5 ), which has an inlet ( 47 ) for the supply of fluid to be purified to a non-filtrate chamber ( 49 ) of the housing ( 1 ), which is separated from a filtrate chamber ( 46 ) of the housing ( 1 ) by the filter medium ( 33 ) of the respective filter element ( 5 ), having an outlet ( 42 ) for filtrate, and comprising a magnetic field-generating unit ( 57 ) arranged inside the non-filtrate chamber ( 49 ), which has an adhering surface ( 51 ) in the form of a sleeve for ferromagnetic particles attached thereto by means of a magnetic force effect. The invention is characterized in that in the non-filtrate chamber ( 49 ), the respective sleeve ( 51 ) extends outside of the respective filter element ( 5 ) parallel to the inlet ( 47 ) and transversely to the outlet ( 42 ), and that the non-filtrate chamber ( 49 ) at least partially encompasses the outlet ( 42 ) at the point of transition to the filtrate chamber ( 46 ).

The invention concerns a filter device for fluids according to thecharacteristics of the preamble of claim 1.

Pre-scalping of ferromagnetic contaminants form the fluid to be filteredusing magnetic force is prior art for filter devices. Plant andmachinery that employs a fluid circuit for lubrication and/or cooling ofmechanical equipment, such as transmissions or pumps, there are alwaysmetal particles present in the fluid through friction during operation,in particular in the instance of transmissions that are under high loadin heavy machinery such as wind turbines or cement mills. Ferromagneticcontamination of the fluid also occurs in other kinds of process fluidsto a varying degree. In particular in detergent solutions often used inplants for the automatic manufacture of parts, a high concentration offerromagnetic particles can be found in the fluid. The separation ofparticles significantly increases the service life of the filterelements, particularly in fluids with high contaminant concentrations.

The documents DE 10 2006 062 807 B4 and DE 10 2013 014 453 A1 discloseexamples of known devices. As a device that generates a magnetic field,said known filter devices use a magnetic rod with permanent magnets,also called a magnetic core, which extends in those devices into theinner space of the respective filter element and is attached to ahousing lid of the filter device. The outside of the magnetic rod formsthe adhering surface on which the metallic particles are deposited inoperation. In order to dispose of the deposits in the known device, thehousing lid has to be unscrewed to be able to remove the magnetic rodtogether with the filter element from the housing. The magnetic rod mustthen be removed from the filter element to be able to remove theparticles that adhere to the outside of the magnetic rod. The removal ofsaid particles is rather difficult since they are retained by themagnetic force on the outside of the magnetic rod. The use of the knownfilter devices thus requires a correspondingly large effort in terms ofmaintenance and time.

The document U.S. Pat. No. 8,636,907 B1 discloses a filter device ofthis kind for fluids, comprising a housing for at least one filterelement, wherein said housing has an inlet for supplying the fluid to becleaned into an unfiltrate chamber of the housing, which is separated bythe filter medium of the respective filter element from a filtrate spaceof the housing, which is provided with an outlet for filtrate,comprising a magnetic field-generating device disposed inside theunfiltrate chamber, which provides an adhering surface for ferromagneticparticles that adhere thereto due to the magnetic force and which isformed by at least one casing that envelopes the associated magneticfield-generating device, where said casing extends from at least oneopening in the housing wall into the unfiltrate chamber and in which therespective magnetic field-generating device may be movably accommodatedin such a way that it can be inserted into the casing and at leastpartially removed from the same.

In the known solution the respective casing of the magneticfield-generating device protrudes into the respective filter elementitself or between said elements, which on the one hand impairs thefiltration of the unfiltrate supplied via the inlet, and on the otherhand makes it more difficult to remove the respective filter element andreplace it with a new one.

Based upon said prior art it is the object of the invention to provide afilter device of the kind described, which is characterised by animproved operating performance, in particular concerning filtration, andprovides an easier way to operate the device.

According to the invention, this object is met by a filter device thatexhibits the characteristics of claim 1 in its entirety.

Due to the fact that, according to the characterising part of claim 1,the respective casing of the associated magnetic field-generating deviceextends outside the respective filter element in the unfiltrate chamber,parallel to the unfiltrate inlet and transverse to the filtrate outlet,and that the unfiltrate chamber surrounds at least partially the outletat the transition point to the filtrate space, the respective magneticfield-generating device is separated from the respective filter elementin the device housing, so that neither the filtration process nor thechange of a used filter element to a new filter element are impaired.

The magnetisable particles introduced via the unfiltrate inlet arealready captured at the inlet point into the housing by the respectivemagnetic field-generating device before they reach the respective filterelement, in that said particles adhere to a casing that essentiallysurrounds the magnetic field-generating device. When removing themoveable, magnetic field-generating device, which in turn removes themagnetic force, the now no longer attracted particles drop away from thecasing and can be easily removed from the unfiltrate chamber, forexample through flushing out. The maintenance effort for removing andhandling of the separated particles is thus significantly reduced withthe filter device according to the invention, wherein the spatialseparation of the particle removal function through the magneticfield-generating device and the other particle removal through therespective filter element inside the common device housing is also acontributing factor.

In a particularly preferred embodiment of the filter device according tothe invention provision is made that the housing, at least in operation,extends along a vertical axis, which is comprised of at least twohousing sections of which the lower housing section is provided with theinlet and the outlet as well as the respective magnetic field-generatingdevice, and that the other housing sections serve to hold at least onefilter element. This makes it possible for the lower housing section topreferably remain stationary with a stand on a floor, and by removingthe respective further housing section the filter elements can be madeaccessible for the replacement process. The remaining filter deviceremains as base on the floor as module on a stand, which makes assemblywith the further modules easier.

In a further preferred embodiment of the filter device according to theinvention provision is made that the bottom of the lower housing sectionis closed and is provided with at least one openable outlet forparticles in such a way that, with a preferably closed filtrate outlet,the unfiltrate flowing in via the inlet flushes off the particlescollected by the respective magnetic field-generating device from saiddevice and/or cleans the lower housing section from contaminatingparticles. In this manner it is possible to promptly discharge themagnetisable particles, captured through the respective magneticfield-generating device, via the openable and closable outlet at thebottom end of the lower housing section over the shortest possible pathfrom the housing of the filter device.

In a particularly space-saving manner provision may be made that at bothsides of the filtrate outlet and arranged at the same level are twoparallel to each other oriented magnetic field-generating devices withtheir casings, which extend at least partially, preferably fully,through the lower housing section with its collecting chamber formagnetisable particles. This makes it possible to establish homogenousmagnetic fields in the vicinity of the inlet.

In particularly advantageous exemplary embodiments the respectivemagnetic field-generating device is comprised of a magnetic rod formedthrough a group of permanent magnets, wherein said magnetic rod ismoveable inside a tubular casing and is accessible at one end of thetubular casing for handling purposes. Whilst the magnetic fieldgenerated by permanent magnets constitutes a preferred exemplaryembodiment, it is apparent that the respective casing may contain aremovable device for generating an electromagnetic field.

The arrangement may advantageously be such that more than one tubularcasing for a respective magnetic field-generating device, such as amagnetic rod, is provided. Said casings may in this instance extend at alateral or vertical distance from each other into the unfiltrate chamberor through the same.

In particularly advantageous exemplary embodiments provision is madethat the lower housing section is provided with a bottom part that formsthe bottom-end closing means, the base of which forms the lower closingmeans of the unfiltrate chamber, which extends along the outside of thefilter medium of the respective filter element upwards, which isdisposed in an axial distance from the base of the bottom part, and thatat least one tubular casing extends in horizontal direction through thepart of the unfiltrate chamber between the base of the bottom part andthe filter element. Thus the respective casing, which forms the adheringsurface, is disposed directly in the inflow section of unfiltrate intothe housing, which causes a pre-scalping of particles before theunfiltrate rises with its non-magnetisable particle contamination to thefilter element with its filter medium located above.

The arrangement may advantageously be such that on an element seat,which establishes the axial distance of the respective filter elementfrom the base of the bottom part, a fluid connection is provided betweenthe inner, hollow space of the filter element, which during thefiltration process forms the filtrate chamber, and an outlet line forfiltrate as part of the outlet, wherein a tubular casing each extendsthrough the unfiltrate chamber on both sides of the outlet line at adistance from the base of the bottom part.

The outlet line may preferably extend coaxial to the vertical axis fromthe element seat to the filtrate outlet or filtrate discharge located atthe base of the bottom part, wherein besides the filtrate outlet anoutlet is provided on the base of the bottom part for the ferromagneticparticles that have dropped from the respective casing. Said additionaloutlet may be provided with a shut-off means that opens up the outletfor the purpose of flushing out the particles when required.

Alternatively, the arrangement may be such that the outlet line extendsfrom the element seat to the filtrate outlet located on the side wall ofthe housing, wherein at the base of the bottom part, coaxial to thevertical axis, the outlet for the ferromagnetic particles, which havedropped from the respective casing, is provided.

In particularly advantageous exemplary embodiments casings are providedin form of tubes that extend from one housing side wall to anotherhousing side wall, wherein said tubes are preferably closed at one endand provide at the other end access for a moveable magnetic rod.

In their inserted state the magnetic rods may extend up to a closed endof the tube, and may be provided with an end section in form of ahandhold at another end of the tube. The protruding section may beprovided with a handhold for manual operation.

The invention will now be described in detail by way of exemplaryembodiments depicted in the drawing.

Shown are in:

FIG. 1 a perspective view of an exemplary embodiment of the filterdevice according to the invention in vertical cross-section;

FIG. 2 a schematically simplified longitudinal section of the exemplaryembodiment in FIG. 1;

FIG. 3 a perspective view of a second exemplary embodiment of the filterdevice according to the invention in vertical cross-section;

FIG. 4 a perspective view of the housing section of the second exemplaryembodiment of the filter device according to the invention, whichaccommodates the bottom part only, shown at a larger scale compared toFIG. 3; and

FIG. 5 a perspective view in horizontal cross-section of the lower partof the housing of the second exemplary embodiment, looking at the baseof the bottom part.

The invention is described by way of exemplary embodiments withreference to the attached drawings, in which, in a circular-cylindricalfilter housing 1, which extends along a vertical axis 3 (FIG. 2), afilter cartridge may be housed, which in the examples shown is formed bytwo filter elements 5 of equal design. The housing 1 is formed by threehousing sections that are screwed together, of which the top section 7is closed off through an upper end section 9, which is provided with acentrally located, closable vent opening 11. Following the upper housingsection 7 is a central, tubular housing section 13, followed by a lowerhousing section 15. This merges into a bottom part 17 that forms thelower housing end, the base 19 of which has a slightly outwards-domedbottom area.

To support the filter cartridge, which is made up of the filter elements5, an element seat 21 is provided in form of an annular member. Saidannular member is provided with a socket-like, axially upwardsprotruding projection 25 that serves as connector for the lower filterelement 5 and as seat for its end cap 23 that faces it, wherein saidprojection 25 surrounds a central opening 27 of the element seat 21. Theprojection 25 that forms the connector is provided on the radially outerside with a bevelled surface that rests against a complementary bevelledsurface that protrudes from the end cap 23 of the filter element 5. Theremaining end caps 23 of the filter elements 5 are also provided withsaid complementary protruding bevelled surfaces, through which the lowerfilter element 5 and the upper filter element 5 are also attached toeach other, wherein a sealing ring is disposed between each of thematching bevelled surfaces, which are not visible in the drawing. Acover means 29 is provided as upper end cover for the filter cartridge,which cups the projection 25 of end cap 23 of the upper filter element5, wherein said cover means 29 is provided with a centrally locatedventing means 31.

As is common practice with such filter arrangements, a fluid-permeablesupporting tube 35 is in contact with the inside of the filter medium 33of the filter elements 5, which extends all the way from the end cap 23located on the element seat 21 to the upper end cap 23 of the upperfilter element 5, and which is strengthened in the upper section througha reinforcement ring 37. The annular member of the element seat 21 isretained on a supporting plate 39, which in turn is attached to thehousing by a coaxially extending tube 41. Beginning from the centralopening 43 of the supporting plate 39, said tube 41 forms the outletthrough which the filtrate flows out from the inner filter cavity 46 ofthe filter cartridge during the filtration process and is discharged viaa filter outlet 42. The tube 41 as part of the filter outlet 42 issupported via radially extending webs 45 on the inner housing wall ofthe lower housing section 15, which extend in radial direction at thetransition from the lower housing section 15 to the bottom part 17.

The tube 41 exits the housing 1 at the base 19 of the bottom part 17coaxial to axis 3. An inlet 47 is provided in the section between thewebs 45 and the supporting plate 39 of the element seat 21 in the sidewall of the housing for the supply of unfiltrate to the part of theunfiltrate chamber 49 that follows inlet 47, which is inside the lowerpart of the housing section 15 and within the following bottom part 17.The unfiltrate chamber 49 extends upwards via the outside of thesupporting plate 39 of the element seat 21 and along the outside of thefilter medium 33 of the filter elements 5 to the upper housing end.

At the level of the lower edge of the inlet 47 and above the webs 45 thetubes 51 extend from one housing side wall to another housing side wall.The tubes 51 extend fully closed from the access openings 53 in thehousing wall and through the entire unfiltrate chamber 49. Thus theinternal space of the tubes 51 is separated from the unfiltrate chamber49 impermeable to fluids. A tube end 52 of the tubes 51 slightlyprotrude from the access openings 53. Each of the protruding tube ends52 of the tubes 51 is closed by a plug 55 that is visible in FIG. 1,whilst the opposite tube ends 52 are open. As is also depicted in FIG.1, the tubes 51 extend parallel to each other as well as horizontal andlaterally beside the pipe 41 that forms the outlet. A magnetic rod 57may be inserted into and retrieved from each of the open tube ends 52 ofpipes 51. Said magnetic rods 57, also called magnetic cores, are made upin the usual manner of a group of consecutive permanent magnets 59 (seeFIG. 4) and are provided at one end with a spherical handhold 61 to beable to easily insert and retrieve the magnetic rods 57 from therespective tube 51.

During the filtration process the tubes 51 are located directly in theinflow section of unfiltrate supplied via inlet 47. Due to the magneticforce generated by the permanent magnets 59 of the magnetic rods 57,which are located inside the tubes 51, ferromagnetic particles aredeposited on the outside of the tubes 51 so that pre-scalping takesplace within the housing section located below the filter elements 5before the unfiltrate rises to the filter cartridge where the filtrationprocess takes place from the outside of the filter medium 33 to theinner filter cavity 46, which forms the filtrate side. For dischargingthe particles that were deposited on the tubes 51, the magnetic rods 57are pulled out of the tubes 51. Due to the resulting removal of themagnetic force the deposited particles drop from the tube 51 to the base19 of the bottom part 17. Besides the tube 41 that forms the dischargeline for the filtrate, there is a particle outlet 63 (not shown) at thebase 19 of the bottom part 17, which opens outlet 63 into an openposition if a discharge of particles that has accumulated on the base 19of the bottom part 17 needs to be carried out. This may simply beachieved by a flushing process in which unfiltrate, which flows in undersystem pressure via inlet 47, flushes the particles out through theopened outlet 63. In this instance it is preferable that the filtrateoutlet 42 on tube 41 is closed so as to apply full system pressure inthe flushing process. Since the tubes 51 are in the flow path of theunfiltrate coming from the inlet 47, any particles that may still adhereto the tubes 51 despite the absence of magnetic force, are carried awayby the flow and thus discharged.

The FIGS. 3 to 5 depict a second exemplary embodiment of the filterdevice according to the invention, which differs from the firstdescribed exemplary embodiment only by a modified design of the housingpart below the element seat 21. Analog to the first exemplaryembodiment, the element seat 21 for the filter cartridge is attachedabove the tube 41 that forms the outlet, which in turn, like the tube 41in the first exemplary embodiment, is fixed via webs 45 that extend inradial direction to the side wall of the housing. In contrast to thefirst exemplary embodiment the tube 51 does not extend coaxially to base19 of bottom part 17 but is angled via an elbow 65 towards the filtrateoutlet 42 by forming part of the same. Said filtrate outlet 42 isdisposed on the side wall of the housing in the section between theelement seat 21 and the tubes 51.

Located on the side opposite to outlet 42 is the unfiltrate inlet 47which, compared to the filtrate outlet 42 is arranged slightly below thesame. With the filtrate outlet 42 in a lateral position, the centralsection of the base 19 of the bottom part 17 is free for the coaxiallyarranged particle outlet 63. The tubes 51, which form the casings forthe magnetic rods 57, are disposed slightly below the unfiltrate inlet47 in the same way as in the first exemplary embodiment at a distancefrom each other, extending parallel and horizontal (see FIG. 5).

The functionality of the second exemplary embodiment corresponds in thisdesign with the first exemplary embodiment, that is, the discharge ofparticles accumulated on tubes 51 may take place through flushing themout via the particle outlet 63 with the magnetic rods 57 removed. Whilstin both exemplary embodiments the tubes 51, which serve as casings forthe magnetic rods 57, are closed by means of plugs 55 at one tube end 52at the same housing side, the plugs 55 may be omitted so that magneticrods 57 may be inserted or removed from any of the housing sides,whichever is better accessible in the installation. It is also possiblethat one tube 51 is closed on one housing side and the other tube 51 isclosed on the other housing side. It is furthermore possible to providea different number of tubes 51 as casings for a corresponding number ofmagnetic rods 57.

1. A filter device for fluids, comprising a housing (1) thataccommodates at least one filter element (5), wherein housing (1) isprovided with an inlet (47) for the supply of fluid to be cleaned to anunfiltrate chamber (49) of housing (1), wherein said unfiltrate chamber(49) is separated from a filtrate chamber (46) of housing (1) throughthe filter medium (33) of the respective filter element (5), whereinsaid filtrate chamber (46) is provided with an outlet (42) for filtrate,and a magnetic field-generating device (57) that is disposed within theunfiltrate chamber (49) and that is provided with an adhering surface(51) for ferromagnetic particles that are deposited there throughmagnetic force, which is formed through at least one casing (51) thatsurrounds the associated magnetic field-generating device (57), whichextends from at least one opening (53) in the housing wall into theunfiltrate chamber (49) and in which the respective magneticfield-generating device (57) is moveably accommodated in such a way thatit may be inserted and at least partially retracted again from thecasing (51), characterised in that the respective casing (51) extendsoutside the respective filter element (5) inside the unfiltrate chamber(49) parallel to inlet (47) and transverse to the outlet (42), and thatthe unfiltrate chamber (49) encloses at least partially the outlet (42)at the point of the transition to the filtrate chamber (46).
 2. Thefilter device according to claim 1, characterised in that the housing(1), at least in operation, extends along a vertical axis (3), which iscomprised of at least two housing sections (7, 13, 15) of which thelower housing section (15) is provided with the inlet (47) and theoutlet (42) as well as the respective magnetic field-generating device(57), and that the other housing sections (7, 13) serve to accommodateat least one filter element (5).
 3. The filter device according to claim1, characterised in that the bottom of the lower housing section (15) isclosed and is provided with at least one openable outlet (63) forparticles in such a way that, with a preferably closed filtrate outlet(42), the unfiltrate flowing in via the inlet (47) flushes off theparticles collected by the respective magnetic field-generating device(57) from said device (57) and/or cleans the lower housing section (15)from contaminating particles.
 4. The filter device according to claim 1,characterised in that at both sides of the filtrate outlet (42) andarranged at the same level are two parallel to each other orientedmagnetic field-generating devices (57) with their casings (51), whichextend at least partially, preferably fully, through the lower housingsection (15).
 5. The filter device according to claim 1, characterisedin that the respective magnetic field-generating device (57) iscomprised of a magnetic rod (57) formed through a group of permanentmagnets (59), wherein said magnetic rod (57) is moveable inside atubular casing (51) and is accessible at one end of the tubular casingfor handling purposes.
 6. The filter device according to claim 1,characterised in that more than one tubular casing (51) for a respectivemagnetic rod (57) is provided.
 7. The filter device according to claim1, characterised in that the lower housing section (15) is provided witha bottom part (17) that forms the bottom-end closing means, the base ofwhich forms the lower closing means of the unfiltrate chamber (49),which extends along the outside of the filter medium (33) of therespective filter element (5) upwards, which is disposed in an axialdistance from the base (19) of the bottom part (17), and that at leastone tubular casing (51) extends in horizontal direction through the partof the unfiltrate chamber (49) between the base (19) of the bottom part(17) and the filter element (5).
 8. The filter device according to claim1, characterised in that on an element seat (21), which establishes theaxial distance of the respective filter element (5) from the base (19)of the bottom part (17), a fluid connection (27, 43) is provided betweenthe inner, hollow space (46) of the filter element (5), which during thefiltration process forms the filtrate chamber, and an outlet line (41)for filtrate as part of the outlet (42), wherein a tubular casing (51)each extends through the unfiltrate chamber (49) on both sides of theoutlet line (41) at a distance from the base (19) of the bottom part(17).
 9. The filter device according to claim 1, characterised in thatthe outlet line (41) extends coaxial to the vertical axis (3) from theelement seat (21) to the filtrate outlet (42) located at the base (19)of the bottom part (17), wherein besides the filtrate outlet (42) anoutlet (63) is provided on the base (19) of the bottom part (17) for theferromagnetic particles that have dropped from the respective casing(51).
 10. The filter device according to claim 1, characterised in thatthe outlet line (41) extends from the element seat (21) to the filtrateoutlet (42) located on the side wall of the housing (1), wherein at thebase (19) of the bottom part (17), coaxial to the vertical axis (3), theoutlet (63) for the ferromagnetic particles, which have dropped from therespective casing (51), is provided.
 11. The filter device according toclaim 1, characterised in that casings are provided in form of tubes(51) that extend from one housing side wall to another housing sidewall, wherein said tubes (51) are preferably closed at one tube end (51)and provide at the other tube end (52) access for a moveable magneticrod (57) each.
 12. The filter device according to claim 1, characterisedin that the magnetic rods (57), when inserted into the casings (51),extend up to a preferably closed end of the tube (52), and protrude withan end section in form of a handhold (61) at another end of the tube(52) to enable manual operation.